Die-casting machine



Nov. 2l, 1950 Filed Feb.l 25, 1949 W. COULTHARD DIE-CASTING MACHINE 2 Sheets-Sheet 1 Attorney NOW 21, 1950 w. c :oUL'rHARD 21,530,760

DIE-CASTING MACHINE A Harney Patented Nov. 21, 1950 DIE-CASTING MACHINE William Coulthard, Scotby, near Carlisle, England Application February 23, 1949, Serial No. 77,850 In Great Britain February 11, 1948 2 Claims.

This invention is for improvements in or relating to die-casting, injection moulding and like machines (hereinafter called die-casting machines) of the kind used for the casting or moulding of articles in metal, plastics or like materials.

The invention is concerned with die-casting and like machines of the type comprising a shooting cylinder or combined metal magazine (i. e. a magazine for the molten metal or other material) and shooting cylinder, a ram or plunger working in the cylinder and operating to shoot the molten metal or other material into the dies or mould.

According to the present invention there is provided a die-casting machine of the kind above specified wherein the shooting cylinder or a combined metal magazine and shooting cylinder is supported, or is adapted to be supported, by the die or die-carrying part of the machine in operative position in relation to the dies. In a preferred embodiment of the invention a combined metal magazine and shooting cylinder is supported from the die-parts, die-carriers or bolsterplates thereon by horizontally disposed pins which permit the required opening movement of the movable die-part whilst maintaining or helping to maintain the metal magazine and shooting cylinder in correct position relatively to the dies or mould.

Major advantages of the arrangement according to the present invention are:

(a) The thrust of the metal forcing plunger or ram working in the shooting cylinder is taken by the dies or bolster-plates and is not communicated (at least directly or to any great extent) to the tie rods and machine frame. This means that a lighter frame construction can be adopted for machines designed to deal with aluminium and like materials than has been possible heretofore, or, alternatively, existing machines at present only capable of dealing with materials such as zinc can readily be modified so as to serve for the production of aluminium and like castings requiring the cold chamber method of manufacture.

(b) It is possible to use die-halves or parts of varying and different thicknesses, longer or shorter metal magazine-supporting pins being used according to the varying thicknesses of the dies. In the present type of split-gate, coldchamber, die-casting machines the iixed half or part of the die has to be of a certain thickness, according to the iixed location of the metal magazine and shooting cylinder on the frame of the machine. The advantage of being able to vary the thickness of the die-parts will be obvious to those skilled in the art of die-casting and the like.

The invention is particularly applicable to diecasting machines of the cold-chamber side-shot or under-shot type. In cold-chamber machines the molten metal is generally ladled into the metal magazine or upper part of the shooting cylinder when the dies are open and the metal forcing plunger is retracted. The invention can, however, be applied to other types of die-casting machines provided there is sufficient space to accommodate the device thereon for the purpose of converting them to cold-chamber machines suitable for the production of castings or mouldings requiring a machine of the cold-chamber type.

One embodiment of the invention as applied to a die-casting machine of the cold-chamber type will now be described by way of example with reference to the accompanying semi-diagrammatic drawings. On the drawings:

Figure 1 is a side elevation of the complete machine,

Figure 2 is a cross-sectional view corresponding to line II-II of Fig. 1, the dies being removed to show the bolster-plate for the xed die-carrier of the machine and also the upper part of the shooting cylinder which is supported from said bolster-plate and die-carrier, the supporting means being in section on the line II-II of Figure 3,

Figure 3 is a side elevation of the bolster-plates, for both the Xed and moving die-carriers, and. the shooting cylinder, and

Figure 4 is a side elevation of the two bolsterplates and a sectional elevation of the combined shooting cylinder and metal magazine, the section being through the vertical axis of the cylinder.

The general construction of the machine shown in Figure l follows existing practice and comprises a frame It supporting a xed die-carrier I I and tie rod guides I 2 for a movable die-carrier I3. Movement of the movable die-carrier is effected by compressed air through a piston and cylinder device I4 under the control of a handoperable valve I5.

The combined metal magazine and shooting cylinder is indicated at I6, see Figure 1, and comprises (see Figures 3, 4 and 5) a cylinder proper Il in which works a piston I8 connected to and operating the shooting ram I9, the latter shooting the molten metal from the metal magazine 20 into the cavities of the mated dies 2| and 22 in the usual way` It will be noted that the metal magazine 20 is supported in the removable plate or cover 23 of the shooting cylinder il. Movement of the piston I8 and ram I5 in the shooting direction is eiected by compressed air admitted by a part-flexible pipe 2li and acting on the underside '25 of the piston i5. Return movement of they piston and ram is effected by compressed air at constant pressure supplied by a part-exible pipe 25 and acting on the annulus 2l of the piston. The compressed air acting on this annulus is only capable oi' eirecting return movement of the piston and ram when the pipe 24 is open to atmosphere. Control of the connection of pipe 2d to the source oi compressed air, to effect a shot and to atmosphere for return movement of the shooting ram is provided by a hand-operable Valve 28.

The combined metal magazine and shooting cylinder, instead of being xed to or integralv with the main frame ofv the machine as has been the case heretofore, constitutes a separate unit suspended from the die-carriers. This is eirected, in the embodiment of the invention shown on the drawings, by providing the cover 23 oi the shooting cylinder I1 with lugs 29 having holes 3|) to receive pins 3|. The heads 32 of the pins 3| (see Figure 3) are trapped in holes 33 in the bolster-plate 34 which is attached te the fixed die-carrier H whilst the forward ends of the pins 3| extend freely forward for a sliding t in bushes 35 in the bolster-plate 36 which is attached. to the movable die-carrier I3. It will be understood that the bolster-plates 34' and 33 carry the diehalves 2| and 22 in the usual way. In addition to the pins 3| screws may be provided for securing the lugs of the shooting cylinder cover to the bolster-plate 34. The pins 3| and the holes in the bushes 35 are aligned correctly s0 'that the bushes will "nd the free ends of the pins and slide smoothly over them as the dies are closed. Thus, when the dies are open, the pins 2| are cantilevers as their one ends are supported by the fixed die carrier and the intermediate pin portions support the shooting cylinder E6. However, when the dies are closed, both ends of the pins are supported by the die carriers so that the reactive stress between the dies 2| and 22 and the shooting cylinder I5 is taken by the pins 3| and not transmitted to the tie rods I2 or frame l0.

It will be appreciated that in the arrangement just described the thickness of the die-parts 2| and 22 is not limited by the necessity of having to locate the split-gates of the dies in alignment with a metal magazine and shooting ram or plunger the position of Vwhich is fixed. With the arrangement just described it is possible by a selection of supporting pins 3| of approximate length and the use of packing pieces between the cover 2.3, carrying the metal magazine, and bolster-plates, if necessary, to position the metal magazine 20 to suit the thickness of the die-parts and the position of the split-gate. The position of the latter depends, of course, on the thickness of the die-parts.

I claim:

1. In a die-casting machine of the type wherein the opposed sides of a frame are connected by parallel tie rods, a die carrier xed on one of the sides of the frame, a cooperative die carrier mounted on the tie rods for movement relative to said xed die carrier, and a shooting cylinder positioned for loading the dies of said carriers, the combination with said xed die carrier of cantilever support pins xed thereto and freely projecting forwardly therefrom towards the movable die carrier, sockets in the movable die carrier fory slidably receiving the free ends of said pins when the dies are closed, and apertured lugs on said shooting cylinder and slidably mounted on said pins, whereby the shooting cylinder is removably suspended from said pins in an operative position in relation to the dies and the reactionary forces between the dies and cylinder are exclusively taken by said pins.

2. In a die-casting machine of the type wherein the opposed sides of a frame are connected by parallel tie rods, a die carrier fixed on one of the sides of the frame, a cooperative die carrier mounted on the tie rods for movement relative to said xed die carrier, and a shooting cylinder positioned for loading the dies of said carriers, the combination with said die carriers of bolster plates removably mounted thereon, cantilever support pins removably inserted through the xed die carrier bolster plate having heads trapped between said plate and die carrier, said pins freely projecting forwardly from said bolster plate towards the movable die carrier, sockets in the movable die carrier bolster plate for slidably receiving the free ends of said pins when the dies are closed, and ape-rtu-red lugs on said shooting cylinder and slidably mounted on said pins, whereby the shooting cylinder is removably suspended from said pins in an operative position in relation to the dies and the reactionary forces between the dies and cylinder are exclusively taken by said bolster plates and pins.

WM. COULTHARD.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Numc-er Name Date 1,891,894 Lester Dec. 20, 1932 1,909,253 Claus May 15, 1933 1,971,652 Haessler Aug. 23, 1934 2,058,875 Smith Jan. 23, 15537 2,112,342 Lester Mar. 29, 1938 2,220,776 Smith Nov. 5, 1940 

